Fuel cells are a device directly converting chemical energy of fuel and air to electricity and heat through an electrochemical reaction. Unlike existing power generating technologies taking processes of fuel combustion, steam generation, turbine driving and generator driving, fuel cells do not have a combustion process or a driving device, and therefore, do not induce environmental problems while providing high efficiency. Such fuel cells are pollution free power generation since air pollution substances such as SOx and NOx are hardly discharged and generation of carbon dioxide is small as well, and have advantages of low noises and non-vibration.
Fuel cells employ various types such as phosphoric acid-type fuel cells (PAFC), alkali-type fuel cells (AFC), polymer electrolyte membrane-type fuel cells (PEMFC), direct methanol fuel cells (DMFC) and solid oxide fuel cells (SOFC), and among these, solid oxide fuel cells have advantages in that high efficiency may be expected unlike thermal power generation and fuel diversity is obtained, and in addition thereto, it is less dependent on high-priced catalysts compared to other fuel cells since solid oxide fuel cells are operated at high temperatures of 800° C. or higher.
However, despite an advantage of increasing electrode activity, a high temperature-operating condition may lead to problems caused by durability and oxidation of metal materials forming a solid oxide fuel cell. Accordingly, many institutes domestic and abroad have made a great deal of efforts in developing medium-low temperature-type solid oxide fuel cells.
As an air electrode material of such medium-low temperature-type solid oxide fuel cells, lanthanum strontium cobalt ferrite (LSCF) is typically used as a perovskite-type (ABO3) oxide particle, and lanthanum strontium cobalt ferrite is a material having highest applicability at medium-low temperatures compared to other compositions in terms of chemical durability, long-term stability and electrical properties.
However, there is still much room for improvement in the lanthanum strontium cobalt ferrite in terms of long-term stability and electrochemical aspects, and such studies are still in process.